xp_cmdshell return code always zero

I have the following sql server 2003 scheduled job that runs a vb.net 2005 console application

DECLARE @rc int

EXEC @rc =  master.dbo.xp_cmdshell '\\server\incomestatement\shopincomestatement.exe'


IF @rc  = 200
BEGIN
  exec dealer_income_error_send_mail
END

IF  @rc  = 0
BEGIN
 exec dealer_income_success_send_mail
END


I thought I read somewhere that I could force a return code by using the following in my vb.net app

If ISProcess.AppPathError = True Then
                Environment.ExitCode = 100
                Exit Sub
            End If

            If ISProcess.AppConfigError = True Then
                Environment.ExitCode = 200
                Exit Sub
            End If

            If ISProcess.LogFileError = True Then
                Environment.ExitCode = 300
                Exit Sub
            End If

            If ISProcess.ErrorFileError = True Then
                Environment.ExitCode = 400
                Exit Sub
            End If

            If ISProcess.errorflag = False Then
                Environment.ExitCode = 0
            Else
                Environment.ExitCode = 911
            End If



By using debug I see that  the  Environment.ExitCode is being set to 200, however it seems the job is
taking the @rc = 0 path

Any ideas?